#include <bits/stdc++.h>
using namespace std;
int main(){
	int n,h;
	scanf("%d",&n);
	if (n>=90 && n<=100){
		h=n*3;
		cout<<h<<endl;
	}
	else if (n<90 && n>=80){
		h=n*2;
		cout<<h<<endl;
	}
	else if (n<80 && n>=70){
		h=n;
		cout<<h<<endl;
	}
	else {
		h=50;
		cout<<h<<endl;
	}
} 
/**************************************************************
	Problem: 1300
	User: xiaojingxuan
	Language: C++
	Result: Accepted
	Time:21 ms
	Memory:2072 kb
****************************************************************/